This invention relates to a pipe liner and more particularly to a replaceable pipe liner assembly of polyurethane or the like for use in lining pipe assemblies for dispensing abrasive materials such as silica sand.
Silica sand for some applications is delivered in hopper trucks that have pipe assemblies at the lower ends of the hoppers for dispensing sand from the truck. These pipe assemblies generally include straight pipe sections joined to T fittings whereby the sand in the hoppers is dispensed from the lower ends of the hoppers, through the T fittings, and into the straight pipe sections where it becomes a common flow of material. These straight pipe sections and T fittings are typically of steel or aluminum. Because of the abrasive nature of silica sand, the sand wears the inner surfaces of the pipes and fittings so that after a relatively short period of time they must be replaced. This is both expensive and places the truck out of service while making the replacements.
It has been known that polyurethane is abrasive resistant, and it has been known to bond polyurethane to the inner surfaces of the T fittings and pipe sections of these pipe assemblies to prolong their life. However, even the bonded polyurethane eventually wears to the point of having to be replaced and this requires either new pipes and fittings with the bonded polyurethane, or returning the worn pipes and fittings to an appropriate facility for rebonding as typically a truck owner would not have the facilities for such a bonding operation. Therefore, even with bonded polyurethane, replacement is relatively expensive and inconvenient.
The present invention overcomes these problems by providing an easily replaceable polyurethane pipe liner assembly which allows the truck owner to replace the liner without replacing the steel or aluminum pipe assembly, at substantially less expense, and without the inconvenience of having to return the truck to a facility for rebonding or replacement.
The replaceable pipe liner assembly of the present invention generally comprises a plurality of tubular polyurethane liner sections positioned in end-to-end abutting contact along the entire length of each straight pipe of the pipe assembly. The outer diameter of each tubular liner section is less than the inner diameter of the pipe to allow ease of insertion of the liner sections into the pipe. Each liner section has means interfitting with an adjacent liner section to axially align the liner sections and present a smooth inner liner wall. The liner sections are slidable within the pipe for insertion of the liner sections into the pipe in interfitting end-to-end engagement.
The invention further comprises a T-shaped liner section for each T fitting of the pipe assembly. The T-shaped liner section has a main tubular portion with an outer diameter less than the inner diameter of the main pipe portion of the T fitting, and a second tubular portion intersecting the main tubular portion with an outer diameter less than the inner diameter of the angled portion of the T fitting. Like the tubular liner sections, the T-shaped liner sections are of molded polyurethane, one-piece, construction. The second tubular portion of the T-shaped liner is foldable inwardly substantially within the main tubular portion for insertion of the T-shaped liner into the fitting and is resilient to release back to its original shape when no longer restrained, as when the T-shaped liner is positioned within the T-fitting with the second tubular portion aligned with the right angle portion of the T-fitting such that it releases from its folded configuration into the right angle portion of the T-fitting. The main tubular portion of the T-shaped liner is in end-to-end engagement with, and is of the same inside diameter as, adjacent tubular liner sections.
Hence, in accordance with the present invention a liner assembly is provided that is easily replaceable so that there is no need to replace parts or all of the pipe assembly itself. Another advantage of the invention is that the liner assembly can be used with pipe assemblies that are already worn, as well as new ones, so long as the worn parts have sufficient structural integrity to support the liner sections.
These and other advantages and features of the invention are apparent from the drawing and detailed description to follow.